Ever since Grote Reber, W9GFZ, produced the first radio map of the Milky Way galaxy in 1937, amateur radio astronomers have delighted in producing visual depictions of the radiation intercepted by their antennas. Here, for example, is a Doppler Shift plot of interstellar hydrogen from the region of the galactic center:

The frequency of hydrogen line radiation, like that of all interstellar signals, is Doppler shifted by relative motion. This drift-scan graph displays time horizontally, frequency vertically, and signal intensity by colors. It shows the rate at which hydrogen sources at the galactic center are moving toward and away from us.

KF9ET image

Click for larger image

Plots such as the above can be produced from an amateur SETI station, by reading the raw data from the Digital Signal Processing (DSP) hardware and software into an ASCII file, and then displaying it graphically in a spreadsheet program (such as Microsoft Excel ®).

The following listing is a QBASIC program for taking power information from SETIFOX POWRDATA.TXT files and
arranging it into a labelled Right Ascension versus Frequency array that can be imported
into a spreadsheet. The program listed below opens a POWRDATA.TXT file located in the
SETIFOX directory and saves the converted text to a file called GALAXY17.TXT in the same
directory. The saved file will have the columns labelled with the frequency and the rows
with the right ascension.